The animal in question starts off with reptile like intelligence, classic gecko and is a singularity, the only individual of his species to be immortal.

It can die and be killed but for the sake of the question we exclude that. Degradation by oxidation, mutation, cancers, viruses don't happen.

Aging is not infinite, it stops after maturity has been reached.

Given that, can a gecko develop intelligence after living so long with a fairly small start?

Intelligence stands for being able to craft and plan ahead the most optimal ways to overcome obstacles of any type. Be it learning how to draw, climb or doing math.

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    $\begingroup$ How do you measure gecko intelligence? What is the threshold that you would consider intelligent given your test? $\endgroup$
    – Raditz_35
    Commented Sep 24, 2018 at 14:34
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    $\begingroup$ Also, do you want sentience or sapience? The difference is the following: sentience: i know that in the mirror is me. Sapience: i am using logic to deduce that the guy with the knive in the mirror behind me might not be friendly. $\endgroup$
    – DarthDonut
    Commented Sep 24, 2018 at 14:39
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    $\begingroup$ Hello. How does immortality work in your world? If your organism simply stops changing after X years, then of course its neural network will not increase it's capacity - but I assume that such a trivial answer is not what you want, and there is something to your immortality you didn't write in your question? $\endgroup$
    – Mołot
    Commented Sep 24, 2018 at 15:04
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    $\begingroup$ Hi Koume. Welcome to Worldbuilding. I often comment on brain related questions because it's of acute personal interest to me. I think you will first have to define intelligence more stringently, or at least define the parameters you are concerned about. My problem solving capability is in the 98th percentile, but my abilities to encode new memories and process words are in the low 40's. My ability to perceive and read normal social cues is next to zero. By your criteria, will I increase in intelligence through more experience? $\endgroup$
    – pojo-guy
    Commented Sep 24, 2018 at 17:46
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    $\begingroup$ Immortality would PREVENT animals becoming intelligent - intelligence is after all an evolved trait. Evolution is about useful traits tending to help with not dying... $\endgroup$ Commented Sep 25, 2018 at 10:58

11 Answers 11


Evidence suggests that no creature becomes more intelligent than it needs to be, intelligence is expensive of calories, for example, human brains are about 2% of our overall mass but require 20% of our minimum calorie intake. So intelligence beyond basic survival needs is actually maladaptive for individuals and species. A gecko therefore has a biological interest in not thinking too much.

To answer your question, no, there are physical limits to how much any brain can handle and a gecko with a gecko brain is not going to be able to learn much more than your run of the mill gecko regardless of how long it lives.

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – L.Dutch
    Commented Sep 26, 2018 at 14:45
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    $\begingroup$ I'm not going to argue about the end conclusion, but the way you reached that conclusion (and by extension the answer itself) is completely erroneous. Evolution can lead to changes in species, not individuals. Individuals don't change (genetically), the population changes based on what sort of individuals (genes) die or survive more often. $\endgroup$
    – ndnenkov
    Commented Sep 26, 2018 at 14:50
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    $\begingroup$ @ndn I don't know what you're reading but I haven't mentioned evolution in any way shape or form. My answer addresses exactly that issue the answer is no a Gecko is a Gecko and always will be. $\endgroup$
    – Ash
    Commented Sep 26, 2018 at 14:53
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    $\begingroup$ Do you assume a human with 160 IQ requires much more energy than a human with 80 IQ? The question is about different intelligence within species. "there are physical limits to how much any brain can handle" Do you say that memory is infinite? $\endgroup$
    – rus9384
    Commented Sep 26, 2018 at 17:04
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    $\begingroup$ @Ash I... don't think you actually know this. Here is a question I asked a few years ago whose answer says exactly otherwise (i.e. - Individuals don't use more energy when doing "complex thinking"). $\endgroup$ Commented Sep 27, 2018 at 21:57

In addition to Ash's answer:

You assume that every lifeform spends its entire life learning indefinitely. This is just plain incorrect. Not only could you look at the elderly of most species and see that at some point the intelligence does not seem to improve anymore or in some cases by tendency degrade in old age. (e.g. Humans)

But some animals learn very little in their lives. Most reptiles are very instinct-driven. They are born with their instincts and live their lives according to them from start to finish.

Not every lifeform even has the ability to learn anything. Just think about training animals. Dogs can easily learn tricks and commands. They have evolved to do that and already started at wolf-intelligence. Other animals are often very difficult to train, hence all the animal abuse scandals in the circus industry - some animals just learn certain things when forced (meaning they are basically tortured). But even then you could not teach every animal every possible trick.

Holy hell, you can't even teach every human everything. I personally know smart people with a great grasp on human psychology, history socioligy and all that, but have severe troubles with math and struggle with concepts that appear to be very basic to other people who study in engineering and science fields.

That does not mean that the math-able people are smarter or better. They are better at math. Intelligence is a very complex issue.

A reptile is not equipped to resemble human intelligence

Unless you have selective pressures favoring intelligence in these species over many, many generations they will not be even close to human intelligence - why would they?

A normal gecko not dying of old age, but well enough equipped to survive on its own has no need for intelligence. What for?
And if it cannot survive on its own then the somewhat-immortality will be of no use to it, either.

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    $\begingroup$ See for example tortoises: lovely animals but dumb as bricks, even the 150 year old ones. They can generally learn that humans = food and scratches but that is just about the limit of their learning. $\endgroup$
    – Borgh
    Commented Sep 25, 2018 at 7:07
  • $\begingroup$ Decline and possibly slower learning in old age comes into conflict with the premise as presumably immortality prevents weakening with age. $\endgroup$
    – PStag
    Commented Sep 25, 2018 at 19:20
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    $\begingroup$ @PStag not necessarily. The brain optimized for cognition in one area over another. There’s evidence that once our brains are formatted one way, it becomes harder to learn other skills. Can’t learn perfect pitch late in life for example (and, yes, that does appear to be a teachable skill to babies). So a late in life inability to learn further is plausible even for an entropy-free immortal. $\endgroup$
    – SRM
    Commented Sep 25, 2018 at 23:28
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    $\begingroup$ @SRM Exactly, the brain has limited capacity depending on its structure. Somebody who already knows 5 languages struggles less with learning a new language than somebody who spoke just a single language all his life. Because his brain has not built the language structures to that extent. Or try to teach somebody in their 40s math if they have never really been using beyond-basic math at any point in their life. Brains are learning machines that are recourse-efficient. They build structures they need early on and elaborate on those later. Building new ones later is very difficult. $\endgroup$ Commented Sep 26, 2018 at 9:37

Yes... and No

Intelligence is much more than gaining experience. The brain must physically be designed to process information, make complex memory associations, store vast amounts of information, etc. etc. The human brain has evolved with cognative capacity, the ability to reason and process information.

Therefore, given immortality, a species already capable of processing information could refine that ability through experience. Chimpanzees, for example, are taught sign language and are capable of expressing complex ideas (complex emotional ideas, not calculus). But I would need to be convinced that, given an infinite amount of time, a Chimp could (through practice alone) learn to design computers.

A gecko is right out.

The problem

The problem is that immortality does not allow for physical change. Take strength training. You can improve the strength of existing muscles to the limit of their physical design — but you can't create new muscles nor exceed the design limits of the muscles. No matter how long you live and press iron, you'll never become Superman.

Said simply, evolution becomes locked in place. An ultra long life-span is actually a detriment. Should one human live forever and the rest of us carry on as normal, then a millennium from now that one human will find themselves less developed (IMO) than the people who lived "naturally," being a whole lot harder to startle from behind, but less developed based on the evolutionary pressures constantly acting on the species. I could easily believe such a person would actually be less intelligent than those who came and went naturally.


So, yes, given an infinite amount of time, a creature will become more intelligent (better said, more experienced) through greater experience and repetition. But, no, regardless the amount of time, a creature who can't be taught to design a computer today won't be capable of designing a computer tomorrow. Or the next day. Or the next day....

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    $\begingroup$ The immortal human would not be "less developed". They would just be not as adapted to the current environment. $\endgroup$
    – forest
    Commented Sep 25, 2018 at 4:59
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    $\begingroup$ @forest is right. The only way the human is less developed is if the environment has continued to become more complex. $\endgroup$
    – SRM
    Commented Sep 25, 2018 at 23:33
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    $\begingroup$ @SRM, I specifically state in my answer, "less developed based on the evolutionary pressures constantly acting on the species." The three of us seem to be in violent agreement. $\endgroup$
    – JBH
    Commented Sep 26, 2018 at 2:31
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    $\begingroup$ Let's just agree to agree then. $\endgroup$
    – forest
    Commented Sep 26, 2018 at 3:02
  • $\begingroup$ Not the clearest phrasing, IMO, but yeah we agree. $\endgroup$
    – SRM
    Commented Sep 26, 2018 at 12:59

Your intelligent geko needs to reproduce

Intelligence is obtained in a species with mutations through evolution, not by making one single individual live longer (some turtles can live up to 200 years, more than any human does actually, and that doesn’t make the turtles more intelligent).

The process works like this: If your gecko is a little more intelligent than the other geckos, and that is an advantage in their current ecosystem, then the intelligent gecko will have more chances to reproduce and distribute its “intelligent genome” to its brood, so the intelligence can evolve IF it is an advantage for the species. But the intelligence of that gecko will not raise just by living longer.


In programming, we have a term "implementation defined behavior." There exists no gecko that lives forever. Thus, what you have is a new creature, with new properties. One of those properties is that it is immortal.


The method in which the gecko achieves that immortality matters. Some methods may cause intelligence to form as a side effect, being the most efficient path to immortality. Or, alternatively, you may find that intelligence is directly opposed to immortality. It's common in Asian cultures to argue that intelligence drives us further away from the balance which is capable of immortality. Some particular solutions may include a predisposition to create the neurological structures we associate with intelligence. Or it may shy away from them all together.

So really it's up to your methods. You decide how it became immortal, and you can decide if it becomes intelligent. Indeed, you get to define what intelligent is. That's one of those words which seems to be nailed down until you start to poke and prod it; then you find out how slippery it is.

All that being said, there are immortal creatures out there. T. dohrnii is a species of jellyfish which is genetically immortal. It can go in both the usual direction from child to adult and the unusual direction from adult to child. (technically from medusa to polyp). Assuming it does not get eaten, it can live forever.

It's not all that intelligent. So the one real-life example of an immortal creature does not appear to automatically lead to intelligence.

  • $\begingroup$ Beautifully stated. This is what I came here to say—that there aren't any immortal geckos, so existing observations can have nothing to say about their intelligence. But using the concept of "implementation defined" to explain that is very clever. :) $\endgroup$
    – Wildcard
    Commented Sep 26, 2018 at 3:27

The short and sweet of it is, immortality and evolution are contradictory.

Evolution requires that the species genetically evolves and then the new replaces the old, through reproduction and death. That is, the new evolved genetic organism replaces the former.

For immortality to be consistent with evolution requires that the individual cells making up the organism themselves mutate, and all new cells that reproduce are made of the new genetic material. However, then these genes have to migrate to every other gene in the organism, or the organism becomes a compilation of many cells that each have a different genetic makeup.

Think in terms of the human body that is made up of hundreds of bacteria, each with its own genetic makeup, working in symbiosis. The mitochondria in our cells, for instance, are actually a separate organism with its own genetic DNA.

So, maybe, if you build the 'intelligence' into symbiotic organisms within the corporate overall body that is immortal, and these sub-organisms can themselves mutate over time, you have a chance at evolving intelligence in a unified corporate body encasing sub-units.

That is, in an extreme way, think of the brain of the organism as a separate entity with its own unique genetic code, that reproduces and dies off, within the overall structure of the gecko. Therefore, the brain can evolve as it dies off and reproduces, even though the body is immortal.

The problem is, every new 'brain' would loose the experiences and knowledge of the old brain, and would have to start all over again. Mind you, this is not necessarily a bad thing. The human mind has a finite storage capacity for new knowledge, memory, and experiences. Replacing it with a new mind every two hundred years or so may not be a bad thing.

  • $\begingroup$ This was a very good read, so +1 from me; however, I would like to point out that immortality isn't necessarily a contradiction of evolution and vice versa. The reason being is that a singular life form, may not be able to evolve on its own; however, two immortal beings can mate and produce another immortal being that could in fact, be mutated (e.g. different from the parents) and thus possibly over millions of years of reproduction, the right mix could happen to allow self evolving immortal beings. Just as life itself was a miracle that should've never happened. $\endgroup$
    – user54342
    Commented Sep 24, 2018 at 21:10
  • $\begingroup$ In theory, the very first single-celled organism that originally started everything could still be alive, and could also have significantly evolved. That is, there could be a continuity established from a cell living today all the way back to the original 'first cell'. But single-cell organisms have an advantage in evolution in that they ARE single cells. They do not require entire systems of cells to share the same mutation. However, they would be limited in intellectual capacity. How much knowledge can a single neuron cell gain? $\endgroup$ Commented Sep 24, 2018 at 22:37
  • $\begingroup$ Mitochondria were separate endosymbiotic organisms. Nowadays, they are just organelles. $\endgroup$
    – forest
    Commented Sep 26, 2018 at 2:04
  • $\begingroup$ @forest Which means that they evolved independent of the host. Precisely my contention. $\endgroup$ Commented Sep 26, 2018 at 2:49

I consider myself really intelligent human and also moderatly adaptable to new ideas even on older age. But I am sure, that even being immortal and given all current knowledge accessible, I would not be able to learn it in whole at any one given time.

I can learn more about computers, but if I will start learning about biology, I would inevitably over time will lost a lot of my computer knoledge. And should I start learning about linquistic, I would lost my biology skills over time too. I probably may (given unlimited time and some reason) learn a top skills in any one particular skill/knowledge/science/... but no way in all of them at the same time. My brain is simply not so big and complicated to be able get it all at one time.

Your gecko have the same problem - his brain is only so big and complicated, so there is only so much to scram in even over unlimited time.

The solution for me and for your gecko would be the same - grow larger and better brain, which also means grom more powerfull body just to support living of such brain. But then we will be something totally different ont only mentally (gecko human-like ineteligent, me being top at all 2018 technologigies), bat also psysically - to the point, that we would not look much similar as the original form.

Evolution solve it with modificating next generations, so each next generation can have something little better, but be a little different. Over last hundred year people are on average smarter and larger, but probably also a little weaker as strenght does not help now so much in success. Long before we was animals of size a rat or what and we surely was not gain todays intelligence, if we would stay in that form and be immortal. The brain is a big limit.


Koume, In order for your gecko to achieve intelligence beyond what it currently has (and are you hoping for near-human intelligence in the end?), the gecko would need to evolve, most likely into something that eventually is no longer gecko. Human ancestors are thought by some scientists to have once been little tree-dwelling bushbaby-type creatures. But along the way, we had opposable thumbs to grasp things and then we walked upright, not only giving us a wider view around us for safety but it freed up our hands to do things other than crawling around on all fours. Your gecko would most likely need to follow these traits (at least to gain human-like intelligence). It would need to evolve into a humanlike creature capable of manipulating things to create tools. There are of course other intelligences such as that of crows/ravens, elephants, octopuses (octipi?), and dolphins whose bodies are very different but have sound reasoning skills. Your gecko could remain a gecko if you suspend disbelief and just have your gecko as being very clever (like the mice from Narnia). But you really have two choices: either your gecko is already smart, or it becomes so through evolution. But immortality wouldn't serve it for growing smarter if it is really happy just eating flies every day and doesn't seek to learn from new adventures.


I don't know how well this can be answered from the point of views of physics. This is because mathematical models of physical systems have all sorts of ridiculous behavior given infinite time. As you may have heard, an immortal monkey typing random letters will eventually write the Hamlet. By similar logic, intelligence can be argued to rise from random fluctuations, see https://en.wikipedia.org/wiki/Boltzmann_brain.

Perhaps you can use this kind of logic to argue that at least one point in time the gecko is in fact very intelligent. However, the immortality of the gecko probably needs to allow at least some sort of fluctuations for this to be possible. It will also take extremely long for the gecko to get smart this way.


Tagging along to what others have said as to the given, that there will be no incentive to self improve as a means to survival, your question asks

"... can a gecko develop intelligence after living so long with a fairly small start? "

It's easy to infer, but not confirm, that you mean whether there is causality between longevity alone and intelligence improvement.

It's up to you whether you want to reconcile your gecko with any mappings of the physiology and biochemistry as they are in the world. We are talking about an immortal gecko after all, it seems rather easy to look past that.

Perhaps find an alternative explanation for the evolution, out of the box of the way Earth species have done it, if you think about it only in mathematical terms, you just change something in a complex system and throw away any instances where the result doesn't survive a criteria, then repeat enough iterations and you will have complex system instances which do meet the criteria.

If you are going to cover for the negligible physiological traits of immortality... (sarcasm) I don't see why you you can't just use a different method to grow your gecko's brain, unlike the one we used to grow ours.


Human intelligence is a product of evolution, not longevity. We may learn more as we gain experience, but it's the "capacity for learning" that we're all born with, that makes us intelligent. Your hypothetical gecko has a much more limited capacity for learning. It also has far more limited sensory experience. It may, for example, process visual input by responding to small dark objects moving against a lighter background, which it instinctively lashes it's tongue out at, without actually producing an image of its surroundings like we do. So it's not even capable of gathering visual information like we do.


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